An electro-photographic type image forming apparatus such as a laser printer and an LED printer is known. A developing cartridge is used in the image forming apparatus. The developing cartridge includes a developing roller for supplying toner. One conventional developing cartridge is capable of being attached to a drawer unit. The drawer unit is positioned in an interior of the image forming apparatus and can be pulled from the inside of the image forming apparatus to the outside of the image forming apparatus. The drawer unit includes a photosensitive drum. The photosensitive drum faces the developing roller when the developing cartridge is attached to the drawer unit.
Further, another conventional developing cartridge is capable of being attached to a drum cartridge. The drum cartridge includes a photosensitive drum. The photosensitive drum faces the developing roller when the developing cartridge is attached to the drum cartridge. When the developing cartridge is attached to the drum cartridge, the photosensitive drum faces a developing roller of the developing cartridge. The developing cartridge is attached to the image forming apparatus in a state where the developing cartridge is attached to the drum cartridge.